>To provide more stats on it, one Web site, the other which is similar with the same set of parameters, is on the same cycle since 8 hours and 49 minutes. That one receives ongoing hits as well. The Universal Thread is recycling every 25 minutes approximately. And, I have been searching to find a difference and I cannot find anything.

IIRC, the log showed the recycling was being triggered by more than the default recompiles being counted. If we assume this reason is correct then it might be interesting to use something like FileMon to track exactly what is happening in the filesystem.

Also there's a posting towards the bottom of this thread that, although old, is interesting:
http://forums.asp.net/t/970884.aspx

Snippets:

Basically, ASP.Net 2.0 runtime uses a FileSystemWatcher to monitor each subdirectory in a web app's root folder. It not only picks up files that got modified, but also files whose last access time changed . If the changes in the folders reach over a certain threshold, ASP.Net will initiate a new deployment.

The reason Microsoft monitors the last access times, besides the last modified times of files and folders, is that when you copy a file to overwrite an existing one, file system will change the file's last access time, while leaving the last modified time alone.

Note that a folder's last access time gets changed even when a process lists the files of the folder without touching any file in it.

But that post is over four years old - I'd expect MS to have modified the behaviour as part of a fix.......

(BTW, when looking at this thread via 'View Entire Thread' I can't find the attachments on earlier posts)